The tire is manufactured by preparing an unvulcanized green tire and vulcanizing the green tire using the tire vulcanization mold while molding it into a predetermined shape. In the tire vulcanization mold, it is required to discharge air accumulated between the mold and the green tire in order to suppress molding defects.
For example, Patent Literature 1 discloses that a side mold for molding a sidewall portion of the tire is divided into a plurality of rings in a tire radial direction, and centering between the rings is performed by forming mating surfaces of each ring as inclined surfaces inclined with respect to a tire axial direction, so that gaps between the rings are made uniform in a tire circumferential direction. However, in this literature, the mating surfaces of the rings are closely fitted and centered, and grooves for discharging the air are provided in the mating surfaces. Therefore, rubber intrudes into the grooves for discharging the air, which causes a poor appearance. Further, this literature discloses as another mode that during manufacture of the mold, the mating surfaces of each ring are temporarily closely fitted and centered and a screw hole is formed for fixing both, and then, each ring is positioned in the tire axial direction using a shim, so that minute gaps for discharging the air are provided on the mating surfaces. However, in this case, since centering between the rings by close contact fit is not performed in a state finally assembled by using the shim, and centering is influenced by machining accuracy of screw holes, it is not easy to make uniform the minute gaps in the tire circumferential direction.
On the other hand, Patent Literatures 2 and 3 disclose that an annular recess is provided in the side mold and an annular ring member is fitted into the annular recess. However, a structure disclosed in Patent Literature 2 does not discharge the air from the gap between the ring member and the annular recess, but discharges the air by separately providing a recessed groove and a vent hole. The structure disclosed in Patent Literature 3 discharges the air from between the ring member and the annular recess, but discharges the air by providing a large number of fine grooves on the mating surfaces of the ring member and the annular recess, and there is a possibility that the rubber may intrude the fine grooves.